Battery module and bus bar assembly

ABSTRACT

A bus bar assembly includes a nonconductive terminal cap configured to at least partially surround an electrically conductive terminal. The terminal cap has a perimeter wall configured to circumscribe at least a portion of the terminal to provide a gap configured to expose the terminal. The terminal cap includes a first attachment feature. The bus bar assembly also includes a bus bar having an end configured to mechanically and electrically engage the terminal in an assembled condition and a nonconductive shroud enclosing the bus bar. The shroud includes a second attachment feature configured to removably engage the first attachment feature in the assembled condition to secure the shroud to the terminal cap. A method of electrically connecting cells of a battery is also provided.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of U.S. patent applicationSer. No. 16/865,315 filed on May 2, 2020, which claims the benefit ofpriority to U.S. Provisional Patent Application No. 62/865,470 filed onJun. 24, 2019, the entire disclosure of which is hereby incorporated byreference.

FIELD OF INVENTION

The disclosure relates to a bus bar used to connect battery cells, forexample.

BACKGROUND

A battery module has multiple battery cells with terminals that areelectrically connected to one another to provide a more powerful batterythan the individual cells would otherwise provide. One common type ofelectrical connection is a cable having terminal rings at opposing ends.Each terminal ring is bolted to one of terminals of one of the cells.Another common type of electrical connection is a bus bar that is boltedto the cells in a similar manner to that of the cable.

The type of battery module used in, for example, automotive applicationsprovides significant electrical energy. It is desirable to design asystem for electrically connecting and disconnecting the cells in amanner that is safe for the battery module assembly and/or servicetechnicians.

SUMMARY

In one exemplary embodiment, a bus bar assembly includes, among otherthings, a nonconductive terminal cap that is configured to at leastpartially surround an electrically conductive terminal. The terminal caphas a perimeter wall that is configured to circumscribe at least aportion of the terminal to provide a gap that is configured to exposethe terminal. The terminal cap includes a first attachment feature. Theterminal cap also includes a bus bar that has an end that is configuredto mechanically and electrically engage the terminal in an assembledcondition. The terminal cap further includes a nonconductive shroud thatencloses the bus bar. The shroud includes a second attachment featurethat is configured to removably engage the first attachment feature inthe assembled condition to secure the shroud to the terminal cap.

In a further embodiment of any of the above, the perimeter wall has aU-shape that is arranged on at least three sides of the terminal. Theperimeter wall extends beyond the terminal.

In a further embodiment of any of the above, the terminal cap has a postthat receives the terminal and is arranged interiorly of the perimeterwall. The terminal is a male terminal. The gap is provided between thepost and the perimeter wall, and the end is a female terminal that isconfigured to mate with the male terminal.

In a further embodiment of any of the above, the terminal has aperimeter edge that bounds opposing faces of the terminal. The postreceives the terminal and surrounds the perimeter edge but leaves atleast one of the faces exposed. The perimeter wall extends beyond thepost. The perimeter wall and the post cooperate to provide the gap asfinger-proof.

In a further embodiment of any of the above, the terminal cap includes afirst notch. The shroud includes a second notch. The first and secondnotches are nested with one another in the assembled condition toenclose the terminal and the end of the bus bar.

In a further embodiment of any of the above, one of the first and secondattachment features is a finger. The other of the first and secondattachment features is a protrusion. The finger and the protrusioninterlock with one another in the assembled condition.

In a further embodiment of any of the above, the shroud includesmultiple shroud portions that cooperate with one another to enclose thebus bar.

In a further embodiment of any of the above, the multiple shroudportions include first and second shroud portions that are nestedrelative to one another in an overlapping relationship.

In a further embodiment of any of the above, the first and second shroudportions engage in a snap-fit relationship in the assembled condition.

In a further embodiment of any of the above, the first shroud portionincludes first and second housings that are secured about a portion ofthe bus bar. The first and second housings are received in an opening inthe second shroud portion.

In a further embodiment of any of the above, the bus bar includes aU-shaped portion that is received in the first shroud portion to providea space between opposing ends of the bus bar. The space is configured toaccommodate an obstruction.

In another exemplary embodiment, a battery module includes, among otherthings, a battery cell that has an electrically conductive terminal. Thebattery module also includes a nonconductive terminal cap that isconfigured to at least partially surround the terminal. The terminal caphas a perimeter wall that is configured to circumscribe at least aportion of the terminal to provide a gap that exposes the terminal. Theterminal cap includes a first attachment feature. The battery modulefurther includes a bus bar that has an end that mechanically andelectrically engages the terminal in an assembled condition. The batterymodule further includes a nonconductive shroud that encloses the busbar. The shroud includes a second attachment feature that removablyengages the first attachment feature in the assembled condition tosecure the shroud to the terminal cap.

In a further embodiment of any of the above, the battery cell is a firstbattery cell and the terminal is a first terminal. The battery modulefurther includes a second battery cell that has a second terminal. Theend is a first end, and the bus bar has a second end that is secured tothe second terminal.

In a further embodiment of any of the above, the perimeter wall has aU-shape that is arranged on at least three sides of the terminal. Theterminal cap has a post that is arranged interiorly of the perimeterwall. The gap is provided between the post and the perimeter wall. Theterminal is a male terminal with a perimeter edge that bounds opposingfaces of the terminal. The post receives the terminal and surrounds theperimeter edge but leaves at least one of the faces exposed. The end isa female terminal that mates with the male terminal.

In a further embodiment of any of the above, the perimeter wall extendsbeyond the post. The post extends beyond the terminal. The perimeterwall and the post cooperate to provide the gap as finger-proof.

In a further embodiment of any of the above, one of the first and secondattachment features is a finger. The other of the first and secondattachment features is a protrusion. The finger and the protrusioninterlock with one another in the assembled condition.

In a further embodiment of any of the above, the shroud includesmultiple shroud portions that cooperate with one another to enclose thebus bar. The multiple shroud portions include first and second shroudportions that are nested relative to one another in an overlappingrelationship.

In another exemplary embodiment, a method of electrically connectingcells of a battery includes, among other things, step a) providing anonconductive terminal cap over a conductive battery cell terminal. Theterminal cap at least partially surrounds the terminal. The terminal isa male terminal. The terminal cap has a perimeter wall that isconfigured to circumscribe at least a portion of the terminal. Theterminal is arranged in a post that shields the terminal. The perimeterwall and the post cooperate to provide a gap that exposes the terminal.The method also includes step b) providing a bus bar assembly with a busbar that has an end that provides a female terminal. A nonconductiveshroud encloses the bus bar with the end that is exposed through theshroud. The method further includes step c) pushing the end into the gapand into engagement with the terminal. The method further includes stepd) mating the shroud to the terminal cap to enclose the end. The matingstep is performed simultaneously with the pushing step c).

In a further embodiment of any of the above, the mating step d) includesconnecting a first attachment feature on the terminal cap to a secondattachment feature on the shroud, The perimeter wall and the postcooperate to provide the gap as finger-proof.

In a further embodiment of any of the above, the bus bar assemblyprovides step b) which includes nesting a first shroud portion relativeto a second shroud portion to enclose the bus bar with the shroud.

BRIEF DESCRIPTION OF THE DRAWINGS

The disclosure can be further understood by reference to the followingdetailed description when considered in connection with the accompanyingdrawings wherein:

FIG. 1 is schematic of a battery module having multiple battery cellselectrically connected to one another with bus bars.

FIG. 2A is a perspective view of a first bus bar assembly secured toterminals of the battery module.

FIG. 2B is a cross-sectional view of the first bus bar assembly takenalong line 2B-2B in FIG. 2A.

FIG. 2C is a cross-sectional view of the first bus bar assembly takenalong line 2C-2C in FIG. 2A.

FIG. 3A is a side view of the first bus bar assembly shown in FIG. 2A.

FIG. 3B is a cross-sectional view of the first bus bar assembly takenalong line 3B-3B in FIG. 3A.

FIG. 4 is an exploded perspective view of the first bus bar assembly inan unassembled condition with respect to a terminal.

FIG. 5A is an exploded view of another terminal for use with the firstbus bar assembly.

FIG. 5B is cross-sectional view of the terminal and portion of the firstbus bar assembly shown in FIG. 5A.

FIG. 6A is a perspective view of a second bus bar assembly.

FIG. 6B is a side view of the second bus bar assembly shown in FIG. 6A.

FIG. 7A is an enlarged perspective view of a portion of the second busbar assembly shown in FIG. 6A.

FIG. 7B is a partial perspective side view of the second bus barassembly with a central shroud portion removed to illustrate the bus barshape.

FIG. 8A is a cross-sectional view of the second bus bar assembly takenalong line 8A-8A in FIG. 6B.

FIG. 8B is cross-sectional view of the second bus bar assembly takenalong line 8B-8B in FIG. 6B.

FIG. 9 is an exploded perspective view of the second bus bar assemblywith the central portion of the bus bar enclosed by a portion of theshroud.

The embodiments, examples and alternatives of the preceding paragraphs,the claims, or the following description and drawings, including any oftheir various aspects or respective individual features, may be takenindependently or in any combination. Features described in connectionwith one embodiment are applicable to all embodiments, unless suchfeatures are incompatible. Like reference numbers and designations inthe various drawings indicate like elements.

DETAILED DESCRIPTION

A battery module 10, or battery pack assembly, is schematicallyillustrated in FIG. 1 . The battery module 10 includes multiple batterycells 12 with positive and negative electrical terminals 14 a, 14 b(generally referred to as “terminal 14”). The terminals 14 of thevarious cells 12 are electrically and mechanically connected to oneanother with bus bar assemblies 16 in a configuration that providessufficient power for large electrical loads, such as automotive hybridpropulsion systems.

Referring to FIGS. 2B, 3A and 3B, the terminal 14 is provided by maleterminal provided by a quadrangular copper plate. It should beunderstood that the terminal 14 may be configured differently, forexample, as a female terminal. There is a potential shock hazard whenthe terminal 14 is left exposed. To mitigate the shock hazard whenconnecting and disconnecting the bus bar assembly 16 from the cells 12,a nonconductive terminal cap 18 is secured to a battery housing 19 by aconnection 17 (FIG. 4 ), for example, snaps. The terminal cap 18 mayalso be integrally formed with the battery housing 19, for example,during a plastic molding process.

As shown in FIGS. 2-4 , the bus bar assembly 16 includes a bus bar 36(FIGS. 2B, 2C and 4 ) substantially enclosed by a nonconductive shroud20. The bus bar 36 has an end 46 provided with a female terminal 47 thatmechanically and electrically engages and mates with the male terminal14 in an assembled condition.

The nonconductive terminal cap 18 at least partially surrounds theterminal 14. In the example, a U-shaped perimeter wall 26 circumscribesat least a portion of the terminal 14, for example, on three sides, toprovide a gap 44 configured to expose the terminal 14 in order toreceive the end 46 with the female terminal 47.

The terminal cap 18 also has a post 38 that receives the terminal 14 andis arranged interiorly of the perimeter wall 26. The terminal 14 has aperimeter edge 40 bounding opposing faces 42 of the terminal 14. Thepost 38 extends outward from a base of the terminal cap 18 and providesan E-shaped configuration with the perimeter wall 26. In the example,the post 38 surrounds the perimeter edge 40 but leaves at least one ofthe faces 42 exposed. In this manner, the post 38 shields at least theend of the terminal 14 from contact. The perimeter wall 26 extendsbeyond the terminal 14 and beyond the post 38 to further isolate theterminal 14. The perimeter wall 26 and the post 38 cooperate to providethe gap 44 as “finger-proof,” that is, preventing undesired contact withthe terminal by a technician.

In this disclosure, “finger-proof” means a configuration that meets thestandard set forth in IEC 60529 entitled “Degrees of Protection Providedby Enclosures” and code IP2XB relating to finger Ingress Protection. The“test finger” is based upon a solid object 12.5 mm in diameter or moreand up to 80 mm long being prevented from entering an enclosure.Furthermore, if a standard test finger 80 mm long and 12 mm in diameterenters the enclosure there will be adequate clearance from live parts,i.e., the terminal. In this manner, the disclosed finger-proof terminalcap 18 prevents a technician from inadvertently touching the terminal 14with the terminal cap 18 in place, for example, during assembly and/orremoval of the bus bar assembly 16 with respect to the cells 12.

The terminal cap 18 includes a first notch 28, and the shroud 20includes a second notch 30. The shroud 20 is retained to the terminalcap 18 in the assembled condition by a retention feature. In theexample, a first attachment feature 22 on the terminal cap 18, such as aprotrusion cooperates with a finger-like second attachment feature 24 onthe shroud 20, as best shown in FIG. 2B. As the shroud 20 and the femaleterminal 47 are pushed into the gap 44 during assembly, the first andsecond notches 28, 30 become nested with one another to enclose theterminal 14 and the end 46 with the female terminal 47 and the fingerbegins to deflect outward as the finger slides over the protrusion.

Once the shroud 20 is fully seated with respect to the terminal cap 18,the second attachment feature 24 removably engages and interlocks withthe first attachment feature 22. Engagement of the first and secondattachment features 22, 24 signifies that the desired mechanical andelectrical engagement between the terminal 14 and the end 46 with thefemale terminal 47 has been achieved, that is, the end 46 has engagedthe face 42 of the male terminal 14 and are safely enclosed. Oncecoupled, the retention feature prevents inadvertent decoupling of thebus bar 36 from the terminal 14 until the fingers and depressed and thebus bar assembly 16 is pulled away from the terminal cap 18.

In the example, the shroud 20 includes multiple shroud portionscooperating with one another to enclose the bus bar 36, which enablesthe bus bar to be serviced and the shroud to be reused. Referring toFIGS. 2B, 2C and 4 , the multiple shroud portions include first andsecond shroud portions 32, 34 nested relative to one another in anoverlapping relationship. The first shroud portion 32 includes a sleeveproviding an opening at one end that receives an end of the secondshroud portion 34. Although retentions features may be used between thefirst and second shroud portions 32, 34, a retention feature is notnecessarily needed as the shroud portions are held together by the firstand second notches 28, 30 when the bus bar assembly 16 is in theassembled condition with respect to the terminal caps 18.

FIGS. 5A-5B illustrate one example variation of the terminal cap 18′configuration. The configuration used in the battery module 10 maydepend upon the particular connection 17′ and housing 19′ arrangement aswell as the given terminal 14 a′.

Another example bus bar assembly 116 is shown in FIGS. 6A-9 . Likenumerals indicate like elements. FIGS. 6A, 6B and 9 illustrate oneexample variation of the terminal cap 18 configuration secured usingdifferent housings 19, 19′. Similar to the first bus bar assembly 16,the nonconductive terminal cap 118 at least partially surrounds theterminal 114. There is a U-shaped perimeter wall 126 circumscribing atleast a portion of the terminal 114 on three sides to provide the gap144 exposing the terminal 114 to receive the end 146 with the femaleterminal 147.

The post 138 receives the terminal 114 interiorly of the perimeter wall126. The post 138 shields the terminal 114 from contact in a mannersimilar to that described above in relation to the first bus barassembly 16. Together the perimeter wall 26 and the post 38 cooperate toprovide the gap 44 as “finger-proof,” that is, preventing undesiredcontact with the terminal by a technician.

Rather than using notches like the first bus bar assembly 16, the secondbus bar assembly 116 is received interiorly of the perimeter wall 126instead of in overlapping relationship. The shroud 120 is retained tothe terminal cap 118 in the assembled condition by a retention feature.The first attachment feature on the terminal cap is not illustrated inthe Figures but is provided by a protrusion cooperates with afinger-like second attachment feature 124 on the shroud 120, as bestshown in FIGS. 6A and 9 . As the shroud 120 and the end 146 with thefemale terminal 147 are pushed into the gap 144 during assembly, the end146 and the finger begins to deflect outward as the finger slides overthe protrusion.

Once the shroud 120 is fully seated with respect to the terminal cap118, the second attachment feature 124 removably engages and interlockswith the first attachment feature. Engagement of the first and secondattachment features signifies that the desired mechanical and electricalengagement between the terminal 114 and the end 146 with the femaleterminal 147 has been achieved, that is, the end 146 has engaged theopposing faces 142 of the male terminal 114 and are safely enclosed.Once coupled, the retention feature prevents inadvertent decoupling ofthe bus bar 136 from the terminal 114 until the fingers and depressedand the bus bar assembly 116 is pulled away from the terminal cap 118.

The shroud 120 includes multiple shroud portions cooperating with oneanother to enclose the bus bar 136, which enables the bus bar to beserviced and the shroud to be reused. The multiple shroud portionsinclude first and second shroud portions 132, 134 nested relative to oneanother in an overlapping relationship. In this example, the secondshroud portion 134 is provided on each of opposing sides of the centralfirst shroud portion 132. The first shroud portion 132 is provided bycover 50 snap-fit to a base 48. The first shroud portion 132 includes asleeve providing an opening at one end that receives a respective end ofthe second shroud portion 134 using a snap-fit 52 when in the assembledcondition. Snap-fits, which include a mating window 54 and a protrusion56, are used to connect the various shroud pieces.

The bus bar 136 includes a U-shaped portion 58 received in the firstshroud portion 132 to provide a space between opposing ends 46 of thebus bar 136. The space accommodates an obstruction 60 arranged betweenthe terminals 14 to enable compact packaging of the battery module 10with respect to other components.

In operation, during assembly of the battery module 10, a nonconductiveterminal cap 18 is provided over a conductive battery cell terminal 14.The terminal caps 18 may be provided as loose pieces that are secured tothe battery housing 19, if desired, or they may be integrated into thehousing. The terminal cap 18 at least partially surrounds the terminal14, which is a male terminal. The terminal cap 18 has a perimeter wall26 configured to circumscribe at least a portion of the terminal 14. Theterminal 14 is arranged in a post 38 that shields the terminal 14. Theperimeter wall 26 and the post 38 cooperate to provide a finger-proofgap 44 that exposes the terminal 14.

A bus bar assembly 16 is provided with a bus bar 36 having an end 46,which is a female terminal. A nonconductive shroud 20 encloses the busbar 36 with the end 46 exposed through the shroud 20. The end 46 of thebus bar assembly 16 is pushed into the gap 44 and into engagement withthe terminal 14 so that the shroud 20 mates to the terminal cap 18 toenclose the end 46. During mating, a first attachment feature 22 on theterminal cap 18 interlocks with a second attachment feature 24 on theshroud 20.

In this manner, the terminal cap can be secured battery cell about theterminal, rendering the terminal finger-safe. Thus, the battery moduleis finger-proof even with the bus bar assemblies disconnected, whichallows for safe assembly and handling of the battery module duringassembly and servicing of the battery module.

It should also be understood that although a particular componentarrangement is disclosed in the illustrated embodiment, otherarrangements will benefit herefrom. Although particular step sequencesare shown, described, and claimed, it should be understood that stepsmay be performed in any order, separated or combined unless otherwiseindicated and will still benefit from the present invention.

Although the different examples have specific components shown in theillustrations, embodiments of this invention are not limited to thoseparticular combinations. It is possible to use some of the components orfeatures from one of the examples in combination with features orcomponents from another one of the examples.

Although an example embodiment has been disclosed, a worker of ordinaryskill in this art would recognize that certain modifications would comewithin the scope of the claims. For that reason, the following claimsshould be studied to determine their true scope and content.

What is claimed is:
 1. A bus bar assembly, comprising: a nonconductiveterminal cap configured to at least partially surround an electricallyconductive terminal, wherein the terminal cap has a perimeter wallconfigured to circumscribe at least a portion of the terminal to providea gap configured to expose the terminal and wherein the terminal capincludes a first attachment feature; a bus bar having an end configuredto mechanically and electrically engage the terminal in an assembledcondition; and a nonconductive shroud enclosing the bus bar.
 2. The busbar assembly of claim 1, wherein the shroud includes a second attachmentfeature configured to removably engage the first attachment feature inthe assembled condition to secure the shroud to the terminal cap.
 3. Thebus bar assembly of claim 1, wherein the perimeter wall has a U-shapearranged on at least three sides of the terminal and wherein theperimeter wall extends beyond the terminal.
 4. The bus bar assembly ofclaim 3, wherein the terminal cap has a post that receives the terminaland is arranged interiorly of the perimeter wall, wherein the terminalis a male terminal, and wherein the end is a female terminal configuredto mate with the male terminal.
 5. The bus bar assembly of claim 4,wherein the gap is provided between the post and the perimeter wall. 6.The bus bar assembly of claim 4, wherein the terminal has a perimeteredge bounding opposing faces of the terminal.
 7. The bus bar assembly ofclaim 6, wherein the post receives the terminal and surrounds theperimeter edge but leaves at least one of the faces exposed.
 8. The busbar assembly of claim 6, wherein the perimeter wall extends beyond thepost and wherein the perimeter wall and the post cooperating to providethe gap as finger-proof.
 9. The bus bar assembly of claim 2, wherein oneof the first and second attachment features is a finger and the other ofthe first and second attachment features is a protrusion.
 10. The busbar assembly of claim 9, wherein the finger and the protrusion areinterlocked with one another in the assembled condition.
 11. The bus barassembly of claim 1, wherein the terminal cap includes a first notch andthe shroud includes a second notch and wherein the first and secondnotches are nested with one another in the assembled condition toenclose the terminal and the end of the bus bar.
 12. The bus barassembly of claim 1, wherein the shroud includes multiple shroudportions cooperating with one another to enclose the bus bar.
 13. Thebus bar assembly of claim 12, wherein the multiple shroud portionsinclude first and second shroud portions nested relative to one anotherin an overlapping relationship.
 14. The bus bar assembly of claim 13,wherein the first and second shroud portions engage in a snap-fitrelationship in the assembled condition.
 15. The bus bar assembly ofclaim 14, wherein the first shroud portion includes first and secondhousings secured about a portion of the bus bar and wherein the firstand second housings are received in an opening in the second shroudportion.
 16. The bus bar assembly of claim 15, wherein the bus barincludes a U-shaped portion received in the first shroud portion toprovide a space between opposing ends of the bus bar and wherein thespace configured to accommodate an obstruction.
 17. A method ofelectrically connecting cells of a battery, comprising the steps of: a)providing a nonconductive terminal cap over a conductive battery cellterminal, wherein the terminal cap at least partially surrounds theterminal, the terminal is a male terminal, wherein the terminal cap hasa perimeter wall is configured to circumscribe at least a portion of theterminal, wherein the terminal is arranged in a post that shields theterminal, and wherein the perimeter wall and the post cooperate toprovide a gap that exposes the terminal; b) providing a bus bar assemblywith a bus bar having an end providing a female terminal and anonconductive shroud enclosing the bus bar with the end exposed throughthe shroud; c) pushing the end into the gap and into engagement with theterminal; and d) mating the shroud to the terminal cap to enclose theend, wherein the mating step is performed simultaneously with thepushing step c).
 18. The method of claim 17, wherein the mating step d)includes connecting a first attachment feature on the terminal cap to asecond attachment feature on the shroud.
 19. The method of claim 18,wherein the perimeter wall and the post cooperate to provide the gap asfinger-proof.
 20. The method of claim 17, wherein the providing step b)includes nesting a first shroud portion relative to a second shroudportion to enclose the bus bar with the shroud.